Electrostatic precipitators are commonly used in a wide variety of industrial applications to remove particulate material from flue gases. Such precipitators typically include a plurality of elongated collector electrodes of a generally planar configuration which are suspended within a chamber through which flue gas is routed. Discharge electrodes, typically in the form of wires, are stationed in proximity to the collector electrodes, and a high DC voltage differential is applied across the discharge and collector electrodes. The resulting electrostatic field therebetween attracts particulate material or flyash from the flue gas to the electrode surfaces. Periodically the precipitator is put through a cleaning operation which typically involves mechanically vibrating the electrodes to shake the flyash loose from the electrode surfaces. The loosen flyash falls into a hopper in the bottom of the chamber from which it is collected for eventual disposal.
As is well understood in the art, the spacings between the discharge and collector electrodes must be maintained essentially constant if the precipitator is to achieve its performance ratings. For example, if the interelectrode spacing decreases, the magnitude of the electrode voltage differential must be decreased to avoid arcing. This reduces the electrostatic field intensity which, in turn, degrades the capability of precipitating out the flyash entrained in the flue gas.
Controlling the positions of the collector electrodes is particularly troublesome since they are quite large in physical size. For example, each collector electrode can be in excess of ten feet wide and twenty feet long in large precipitator designs. Because of this large size, each collector electrode typically consists of a plurality of elongated, narrow electrode panels separately suspended in lateral edge-to-edge, essentially coplanar relation to make up the full collector electrode width. The lower ends of these individual collector electrode panels must then be maintained in alignment during precipitator operation. Means to this end must however accommodate limited movements of the electrode panels caused by thermal expansion and contraction and during the cleaning operation when they are mechanically vibrated by means such as a rapping mechanism. Such alignment maintaining devices should also be designed to resist excessive flyash buildup which in time could constrain this limited electrode panel movement, causing them to bow and thus alter their spacings with the discharge electrodes. In the extreme, the electrode panels could become unhooked from their suspension mounting hangers. In addition, such alignment maintaining devices should be of sufficient strength to resist distortion should the underlying hopper backup to the point where it becomes immersed in flyash.